So-called cable conveyors currently and previously in use comprise a cable or chain trained about spaced-apart sprockets and through a closed conduit. Spaced flights or lugs are secured to the cable and the material to be moved is fed to the unit to be pushed through the conduit in a dense plug-flow manner. Customarily, these conveyors run at relatively low speed and have a correspondingly low capacity. Attempts to operate at high speeds have resulted in rapid wearing of the conduit walls due to friction of the material being transported and also to jamming of the material.